We report on the record-high pulse energy of nearly 1.7 μJ obtained directly from a self-mode-locked all-fiber erbium laser with a linear-ring cavity owing its extreme elongation up to several kilometers. Specially selected telecommunication fibers, providing large normal net cavity dispersion in the vicinity of 1.55 μm, have been used for this purpose. Along with compensation for polarization instability in the longer linear arm of the cavity, such approach has ensured stable wavebreaking-free mode-locked lasing with an ultra-low pulse repetition rate of 35
Materials
with electrically tunable optical properties offer a
wide range of opportunities for photonic applications. The optical
properties of the single-walled carbon nanotubes (SWCNTs) can be significantly
altered in the near-infrared region by means of electrochemical doping.
The states’ filling, which is responsible for the optical absorption
suppression under doping, also alters the nonlinear optical response
of the material. Here, for the first time we report that the electrochemical
doping can tailor the nonlinear optical absorption of SWCNT films
and demonstrate its application to control pulsed fiber laser generation.
With a pump–probe technique, we show that under an applied
voltage below 2 V the photobleaching of the material can be gradually
reduced and even turned to photoinduced absorption. Furthermore, we
integrated a carbon nanotube electrochemical cell on a side-polished
fiber to tune the absorption saturation and implemented it into the
fully polarization-maintaining fiber laser. We show that the pulse
generation regime can be reversibly switched between femtosecond mode-locking
and microsecond Q-switching using different gate voltages. This approach
paves the road toward carbon nanotube optical devices with tunable
nonlinearity.
We propose the design of a novel γ-shaped fiber laser resonator and apply it to build a long-cavity normaldispersion mode-locked Er-fiber laser which features enhanced functionalities for management and optimization of pulsed lasing regimes. We report the generation of sub-nanosecond pulses with the energy of ∼ 0.5 µJ at a kilohertz-scale repetition rate in an all-fiber system based on the new laser design. A combination of special design solutions in the laser, such as polarization instability compensation in the ultra-long arm of the resonator, intra-cavity spectral selection of radiation with a broadband fiber Bragg grating, and polarization selection by means of a tilted refractive index grating, ensures low amplified spontaneous emission (ASE) noise and high stability of the laser system output parameters.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.